RE: Finding material which can fulfill certain requirements

RE: Finding material which can fulfill certain requirements

Have you looked at the lowest carbon steel that will make your strength.
You want a steel with low Mn and Cr.
Aside from strength pure Fe comes as closest to your requirements.
A word of warning, all of the low expansion alloys will rust, they are not corrosion resistant.
Though Ti 6-4 may be worth looking at as well. It has low density, low heat capacity, and low thermal expansion.

RE: Finding material which can fulfill certain requirements

Try Carpenter Pyromet® Alloy CTX or Thermo-Span® Alloy.
Pyromet® Alloy CTX is a low expansion superalloy with a CTE about 7.6 ppm/C at 300-400C.
Thermo-Span® Alloy shows about 9 ppm/C at 350C. It is a precipitation hardenable superalloy which exhibits high tensile and rupture strengths, and good thermal fatigue resistance. It offers a significant improvement in environmental resistance over Pyromet® alloys CTX due to the addition of chromium.

RE: Finding material which can fulfill certain requirements

In addition to all the thoughtful comments by everyone else... here some auxiliary comments/ideas.

You may find the following document useful in a limited way. Metal dimensional changes are rarely linear. The following document discusses these changes and lists many material types/alloys and their dimensional change coefficients across a wide range of /\ temperatures. These should be carefully considered when heating and cooling Your tooling... especially from a warpage/thermal-fatigue perspective. May also help You understand how long it could take for Your metal tooling to become fully stable/heat-soaked [especially with significant differences in thickness across the tool].

SAE AIR809 Metal Dimensional Change with Temperature.

CAUTION. Many metals experience measureable contraction or expansion when taken from one heat treat-state [condition] to another [stable] heat treat state [condition].

CAUTION. 'Thermal fatigue' MAY be an issue You will have to deal with in high volume production and high soaking temperatures [75F-to-500F?? or 24C-to-500C???... there is a huge difference in overall expansion/strains]. For this reason the heat-up and cool-down cycles must considered... perhaps even segmenting the tool into shorter elements to minimize over-all expansion/contraction... or perhaps consider ceramic tooling.

Regards, Wil Taylor

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